The use of separate sealing devices (“seals”) between components in a laser machining head is generally known. Such seals are normally elastomeric seals such as O rings. However, it has been shown in practice that the use of separate seals has not proven satisfactory in the removal and subsequent re-assembly of the laser machining head in maintenance work. Either the old seal, which in most cases is no longer intact, is nevertheless re-used, or left out entirely. It may also be the case that a new seal is installed incorrectly. Elastomeric seals have the added disadvantage that the thermal loading capacity of such seals is rather low.
In some cases, components with flat surfaces are used to avoid the need for separate sealing devices.
With laser cutting heads in particular, an insulator of a capacitively insulating material, such as ceramic, of a sensor device, must be connected to a metal component of the laser cutting head in a largely gas-tight, releasable manner. Such a sensor device is disclosed, for example in DE19906442, which is incorporated in its entirety herein by reference. The sealing action between the metal surface and the ceramic surface is dependent on the surface condition of the surfaces (flatness and roughness). A sealing action without a separate seal is difficult to achieve in this case.